1. Technical Field
Embodiments of the subject matter disclosed herein generally relate to methods and systems and, more particularly, to mechanisms and techniques for providing pneumatic power from a fixed part to a rotating part via an inflatable seal.
2. Discussion of the Background
During the past years, with the increase in price of fossil fuels, the interest in developing new production fields has dramatically increased. However, due to continuous exploration, the fossil fuels reserves are now found deeper and deeper either underground or undersea. The oil platforms or rigs used for deep exploration are becoming more complex. Due to these reasons, the cost of a rig is large. Thus, any maintenance aspect of the rig that requires halting the oil production and forcing the rig to stay idle is desirable to be as short as possible and as rare as possible.
One component that often requires maintenance is a drill string internal blowout preventer (“IBOP”), sometimes called a “kelly valve” or a “kelly cock.” This component is used to seal off the drill string until measures can be taken to control a kick that may appear inside the drill string. An IBOP is sometimes called a “kelly valve” because, on older-style rigs, the IBOP was typically located near the “kelly,” which is a non-circular part of the drill string that is used to impart rotary motion to the drill string.
A traditional BOP 10, which is shown in FIG. 1, includes a ball valve 12 or other type of valve disposed in a drill line 14. The ball valve 12 is open as shown in FIG. 1 when the drill line 14 rotates, thus allowing a fluid to circulate through the drill line 14. When necessary, the drill line 14 is stopped and the ball valve 12 is actuated to close the inside of the drill line 14, such that a portion 16 of the drill line 14 is fluidly isolated from a portion 18 of the drill line 14. To actuate the ball valve 12, the ball valve, which is connected in line with the drill string, is connected to an air source 20 as shown in FIG. 2.
The air source 20, typically a pressurized cylinder, is generally stationary. Thus, the pressurized air is provided via pipes 22 and 24 to corresponding inlets 26 and 28 to a rotating section 30. The rotating section 30 includes a fixed part 32 and a rotating part (not shown as being covered by the fixed part 32) that is fixed to the drill line 14. The pressurized air travels from the fixed part 32 to the rotating part and then exits via outlets 34 and 36. From here, the air travels via pipes 38 and 40 to an actuator 42. Actuator 42, when provided with the compressed air, closes or opens the ball valve 12, which is provided inside the drill line 14, under the actuator 42 in FIG. 2.
To minimize air loss between the fixed part 32 and the rotating part, various seals are provided on either of the parts to contact the opposite part. However, the rotation of the rotating part and the permanent contact between the seal and the rotating part makes the seal to quickly wear. A replacement seal needs to be put in place as often as two to sixteen weeks of drilling service. The replacement requires that the entire rig be shut down, which is not cost effective.
Accordingly, it would be desirable to provide systems and methods that extend the replacement period of such seals.